The invention refers to a lockable tamperproof box for sales presentation of compact disk cassettes, audio tape cassettes, video cassettes or the like, which requires a special tool to unlock it. Boxes of this kind are also described in technical jargon as xe2x80x9cSafersxe2x80x9d. The invention refers in particular to a tamperproof box in which, when the cassette is inserted into an insertion aperture of the box, a rear part of a locking device is shifted in the direction of insertion into a lock-in position and in which a front part of this device is equipped with a locking element for the insertion aperture.
Lockable tamperproof boxes of this kind are generally provided internally with electronically or magnetically remotely detectable elements, such as e.g. resonance labels, and are used in retail outlets that are equipped with the related detection systems for the purpose of theft prevention. Any attempt to steal a cassette together with the tamperproof box causes the detectable element inside the tamperproof box to be detected and an alarm to be set off. In the case of a regular purchase, however, the cassettes are removed by the sales staff with a special tool from the tamperproof box, which can then be filled again and re-used.
In order to serve their purpose, tamperproof boxes must not add too much to the cassettes, i.e. they must not be too voluminous, must enable the cassettes they contain to be easily recognised, and yet must on the other hand surround the cassettes so firmly and securely that any unauthorised removal of the cassette or of a data or music medium contained therein is not readily possible. In order to be repeatedly useable, they must be sufficiently robust and, as they are required in large quantities, they must also be cheap. Cassette insertion and extraction operations should be as simple as possible.
A tamperproof box of the kind described at the beginning is known for example from EP 0 508 201 B1. In this case, the locking device comprises a flexible one-piece, bow-shaped accessory element made of magnetic material, which is provided with a longitudinal slit along one of the narrow sides of the box wall conducted between two longitudinally movable terminal buffers and with limbs protruding inwards at both ends, by which the cassette is gripped clamp-wise during insertion and also while it remains inserted. When the cassette is inserted, a locking catch on the inner or rear end of the accessory element is engaged in a slit in the box housing. A strong magnet is necessary to open this locking device, while the cassette is pulled out together with the accessory element at the same time. In the position of the external or front terminal buffer, the extremity of the accessory element protruding from the box can be bent outwards when the clamp around the cassette is freed. It is also necessary to bend the element outwards in the same way when the box is filled. The known tamperproof box is preferably self-locking.
In the tamperproof box known from EP 0 451 189 B1, on the other hand, it is necessary to lock the locking device affixed to it on the outside after the cassette has been inserted by hand, using an external bolt. If this operation is overlooked, the cassette remains unprotected.
In both of the known embodiments, it is relatively simple to lock the box unintentionally without any cassette having been inserted. In the case of the tamperproof box as per EP 0 508 201 B1, this is because the external end of the accessory element protrudes from the cassette. In the case of the box as per EP 0 451 189 B1 A, the bolt described is necessarily freely accessible.
It is the task of the invention to provide a tamperproof box for cassettes that satisfies the demands already described and is also self-locking. In addition, it should also be possible to fill the box automatically in an easy manner and to avoid unintentional locking without any cassette having been inserted. This task is fulfilled by equipping a tamperproof box of the type named at the beginning with a front part that, when the cassette is inserted, is rotated about the direction of insertion by forced coupling with the rear part into a position in which the locking element is swivelled into the insertion aperture.
If no cassette is inserted into the box, the locking element is swivelled out of the insertion aperture, which remains completely free. This enables the box to be filled e.g. letting the cassette drop directly from above into the open insertion aperture, a process that can easily be automated.
As the front part of the locking device takes the form of a swivel component that only rotates when the rear part situated deeper in the box is activated, no part of the locking device protrudes from the box when it is empty and also no actuating element of this device is externally accessible. Any unintentional locking of the locking device is thus avoided.
The box according to the invention is preferably divided into two chambers, one of which has the purpose of holding the cassette and the other of housing the locking mechanism.
The forced coupling between the rear and the front part may take the form of a connecting device, whereby the front part preferably takes the form of a sheath and the rear part preferably takes the form of a rod and the rear part engages the front part with a cam follower in a guiding connection.
In one preferred embodiment, the rear part can be caught into the lock-in position by means of a catch element, whereby the catch element is preferably a leaf spring made of magnetic material clamped on one side into one wall of the box, whose free end automatically connects into a lock catch formed on the rear part when the rear part is pushed into the catch position.
In order to facilitate removal of a cassette from the tamperproof box, the rear part can be pre-loaded by a spring against the direction of insertion opposite the box housing. The spring is loaded further when a cassette is pushed in. As a further advantage, the spring holds the locking device open when the box is empty, i.e. not locked, that that it can be filled instantly.
The width of the chamber that receives the cassette can be chosen substantially to equal the width of the insertion aperture. This embodiment offers the possibility of forming the locking element as an arm, connected to the rotating front part, that swivels into the insertion aperture behind a cassette when it is inserted in the direction of insertion.
An alternative embodiment offers the option to choose the width of the chamber that houses the cassette slightly larger than the width of the insertion aperture. In this case, the locking element can be formed as a catch, connected to the rotating front part, that swivels into the insertion aperture next to the cassette when it is inserted.
For the purpose of displaying the cassettes to the best advantage, the chamber that houses the cassette should be formed at least partly transparent and/or partly open to the exterior. The chamber containing the locking device then has a preferably closed form on the outside and is not transparent, in order to render unauthorised handling and any understanding of the locking mechanism more difficult.